Hi. Today I want to introduce another interesting gadget. I’ll start with the fact that I go to work by bike, my way is through a park where a lot of people. So I have long pondered loud bicycle bell. Wandering through the Internet on the resource vrtp.ru i found a scheme of the car police style siren. I really liked it and I decided to make it for myself .

Scheme is without any changes of its original I’ve added just step-up transformer for that I took from Chinese buzzer keychain.

After the bewitchment in the program EAGLE got this board:

I then developed a 3D model of of the case in the program Rhinoceros 3D